1. Field of the Invention
The present invention generally relates to a cooling device of an electronic device, and particularly relates to a cooling device of an electronic device for cooling the electronic device with use of cooling water.
2. Description of the Related Art
In recent years, while electronic devices such as semiconductors have been developed to have higher density and higher speed, treatment of heat generated by the electronic devices is becoming a growing problem. When the heat generated by an electronic device increases to exceed the capacity of natural heat radiation with use of a radiation fin or the like, the device is forcibly cooled by a cooling device (as disclosed, for example, in Japanese Patent Laid-Open publication No. 10-213370).
FIG. 1 is an example of a related-art cooling device 1. As shown in the figure, the related-art cooing device 1 comprises a cooling section 2, a heat exchanging section 3, a tank 4, a pump 5 and pipes 8A through 8D. The tank 4 stores cooling water therein, and the pump 5 takes suction on the cooling water from the tank 4 through the pipe 8A to feed the water to the pipe 8B connected to the cooling section 2.
The cooling section 2 comprises a tabular cooling plate 2a having a cooling curved pipe 9 therein. The cooling section 2 is thermally connected to an electronic device 6 (installed on a substrate 7) as a heating element. The heat generated in the electronic device 6 is therefore transferred to the cooling water flowing in the cooling curved pipe 9 through the tabular cooling plate 2a. The electronic device 6 is thus cooled by the cooling section 2.
The cooling section 2 and the heat exchanging section 3 are connected by the pipe 8C. The cooling water heated by the cooling section 2 is sent to the heat exchanging section 3. The heat exchanging section 3 comprises a heat exchanging curved pipe 10 and a fan 11. The cooling air generated by the fan 11 is sent toward the heat exchanging curved pipe 10.
Accordingly, the heat of the cooling water is transferred so as to heat the cooling air, so that the temperature of the cooling water is lowered. The cooling water thus cooled passes through the pipe 8D and reaches the tank 4 again to be stored in the tank 4. The cooling water circulates in the cooling device 1 as described above while cooling the electronic device 6. The flowing direction of the cooling water is shown by the chain line arrows in FIG. 1.
In the related-art cooling device 1, however, the cooling section 2, the heat exchanging section 3, the tank 4 and the pump 5 are independent units arranged separately. Therefore, plural relatively long pipes 8A through 8D are required in order to connect devices 2 through 5 of the cooling device 1.
With such long pipes 8A thorough 8D, the heat absorption and heat radiation of the cooling water in the process of flowing in the pipes 8A to 8C heavily affect the cooling of the electronic device 6, resulting in worsening the heat transfer efficiency of the cooling device 1. Also, such long pipes 8A thorough 8D increase the pressure loss caused in the pipes 8A thorough 8D while the cooling water is passing thorough the devices 2 thorough 5, and therefore a pump 5 with a high capacity must be used. Accordingly, the size of the pump 5 is increased, so that the size of the cooling device is increased as well.